scholarly journals The microsporidian spore invasion tube. II. Role of calcium in the activation of invasion tube discharge.

1982 ◽  
Vol 93 (3) ◽  
pp. 970-975 ◽  
Author(s):  
E Weidner ◽  
W Byrd
Keyword(s):  
Calcium Ionophore ◽  
Initial Step ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Color Spectrum ◽  
Microsporidian Spore ◽  
Spectrum Characteristic ◽  
Internal Calcium ◽  
Citrate Phosphate

A swelling response by the polaroplast organelle initiated microsporidian invasion tube extrusions by Glugea hertwigi spores. The tumescence was induced by the displacement of internal calcium. Sodium citrate, phosphate, and the calcium ionophore A23187 were effective in initiating polaroplast swelling and spore discharge; however, the addition of external CaCl2 switched the expanded polaroplasts to a contracted state and blocked spore discharge. Unlike CaCl2, equivalent concentrations of KCl, NaCl, MgCl2, and BaCl2 did not induced polaroplast contraction, and spore discharge was not blocked. 45CaCl2 readily incorporated into spores with expanded polaroplasts; however, little calcium uptake was apparent in spores with contracted polaroplasts. Metallochromic arsenazo III yielded a color spectrum characteristic of the dye-Ca++ complex in the polaroplast region; furthermore, a membrane association with calcium was indicated by strong chlorotetracycline fluorescence within the polaroplast; this fluorescence was extinguished by pretreating spores with ionophore A23187. An association of the membrane with calcium was also indicated by a potassium ferrocyanide-osmium tetroxide technique. All evidence indicates that an internal calcium displacement is an important initial step in the swelling response of the polaroplast organelle.

Tobacco smoke releases performed mediators from canine mast cells and modulates prostaglandin production

1992 ◽  
Vol 263 (1) ◽  
pp. L67-L72
Author(s):  
P. S. Thomas ◽  
R. E. Schreck ◽  
S. C. Lazarus
Keyword(s):  
Mast Cells ◽  
Tobacco Smoke ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Prostaglandin D2 ◽  
Ionophore A23187 ◽  
Temperature Dependent ◽  
Prostaglandin Production ◽  
Lungs And Airways

The role of an extract of tobacco smoke in activating mast cells was studied. With the use of isolated, canine mast cells as a model, we found that cigarette smoke solution (CSS) induced the release of the performed mediators histamine and tryptase from these cells in an energy- and temperature-dependent, non-cytotoxic manner. There was no requirement for extracellular calcium. Nicotine tartrate did not reproduce the effect of CSS. Interestingly, mast cells produced little prostaglandin D2 (PGD2) in response to the CSS, and there was a concentration-related inhibition of calcium ionophore A23187-induced PGD2 synthesis. This suggests at least two mechanisms acting on the mast cell: tobacco smoke can directly activate mast cells to release performed mediators and can simultaneously inhibit prostaglandin production. These observations suggest a mechanism by which mast cells may participate in the bronchospastic and proinflammatory changes seen in the lungs and airways of smokers.

Leptin is involved in acrosome reaction by facilitating activation of MAPK cascades in the Chinese mitten crab, Eriocheir sinensis

2020 ◽  
Vol 70 (1) ◽  
pp. 81-95
Author(s):  
Qing Li ◽  
Haitao Zhao ◽  
Lin He ◽  
Hongdan Yang ◽  
Qun Wang
Keyword(s):  
Acrosome Reaction ◽  
Calcium Ionophore ◽  
Eriocheir Sinensis ◽  
Calcium Ionophore A23187 ◽  
Mitogen Activated Protein Kinase ◽  
Ionophore A23187 ◽  
Mapk Cascades ◽  
Mitten Crab ◽  
Mitogen Activated Protein

Abstract The role of leptin has been documented in several studies, including activated threonine phosphorylation of extracellular signal-regulated kinase (ERK1/2) in the reproduction of rodents and humans. Our previous studies have demonstrated that mitogen-activated protein kinase (MAPK) cascades ERK, P38, and c-Jun N-terminal kinase (JNK) are involved in the spermatogenesis and acrosome reaction of Eriocheir sinensis. Therefore, the aim of this study was to investigate the expression of leptin and its receptor (LepR), and the effect of leptin on MAPK cascades during calcium ionophore A23187-induced spermatozoa acrosome reaction in crabs. Successful western blotting revealed a 16 kDa band for leptin, and 120 kDa and 90 kDa bands for the obese receptor (LepR), respectively, in the tested male reproductive tissues. Both leptin and LepR were localized at the pro-acrosomal vesicle and apical cap (AC) of spermatids, suggesting their role in the subsequent acrosome reaction. Moreover, acrosome reaction can be enhanced by leptin, and this effect decreased due to the anti-LepR antibody. Afterwards, we investigated the effects of leptin on MAPK cascades. The results showed that leptin mainly activated the phosphorylation of ERK, P38 and JNK proteins in the apical cap during the acrosome reaction in crab spermatozoa. This study addresses the role of leptin on spermatozoa, and suggests that leptin may induce molecular changes associated with spermatozoa during acrosome reaction.

scholarly journals Nitric oxide and peroxynitrite trigger and enhance release of neutrophil extracellular traps

2019 ◽  
Vol 77 (15) ◽  
pp. 3059-3075 ◽  
Author(s):  
Aneta Manda-Handzlik ◽  
Weronika Bystrzycka ◽  
Adrianna Cieloch ◽  
Eliza Glodkowska-Mrowka ◽  
Ewa Jankowska-Steifer ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitrosative Stress ◽  
Calcium Ionophore ◽  
Neutrophil Extracellular Traps ◽  
Calcium Ionophore A23187 ◽  
Human Neutrophils ◽  
Ionophore A23187 ◽  
Inflammatory Reactions ◽  
Extracellular Traps

Abstract Despite great interest, the mechanism of neutrophil extracellular traps (NETs) release is not fully understood and some aspects of this process, e.g. the role of reactive nitrogen species (RNS), still remain unclear. Therefore, our aim was to investigate the mechanisms underlying RNS-induced formation of NETs and contribution of RNS to NETs release triggered by various physiological and synthetic stimuli. The involvement of RNS in NETs formation was studied in primary human neutrophils and differentiated human promyelocytic leukemia cells (HL-60 cells). RNS (peroxynitrite and nitric oxide) efficiently induced NETs release and potentiated NETs-inducing properties of platelet activating factor and lipopolysaccharide. RNS-induced NETs formation was independent of autophagy and histone citrullination, but dependent on the activity of phosphoinositide 3-kinases (PI3K) and myeloperoxidase, as well as selective degradation of histones H2A and H2B by neutrophil elastase. Additionally, NADPH oxidase activity was required to release NETs upon stimulation with NO, as shown in NADPH-deficient neutrophils isolated from patients with chronic granulomatous disease. The role of RNS was further supported by increased RNS synthesis upon stimulation of NETs release with phorbol 12-myristate 13-acetate and calcium ionophore A23187. Scavenging or inhibition of RNS formation diminished NETs release triggered by these stimuli while scavenging of peroxynitrite inhibited NO-induced NETs formation. Our data suggest that RNS may act as mediators and inducers of NETs release. These processes are PI3K-dependent and ROS-dependent. Since inflammatory reactions are often accompanied by nitrosative stress and NETs formation, our studies shed a new light on possible mechanisms engaged in various immune-mediated conditions.

Myocardial and endothelial dysfunction after multiple, brief coronary occlusions: role of oxygen radicals

1992 ◽  
Vol 263 (6) ◽  
pp. H1703-H1709 ◽  
Author(s):  
G. J. Gross ◽  
S. T. O'Rourke ◽  
L. R. Pelc ◽  
D. C. Warltier
Keyword(s):  
Free Radicals ◽  
Coronary Artery ◽  
Contractile Function ◽  
Calcium Ionophore ◽  
Endothelial Damage ◽  
Calcium Ionophore A23187 ◽  
Stunned Myocardium ◽  
Ionophore A23187 ◽  
Oxygen Derived Free Radicals

The major objective of the present study was to determine the effect of multiple, brief periods of coronary artery occlusion and reperfusion on postischemic contractile function (sonomicrometry) and endothelium-dependent vasodilator responses in isolated conduit coronary artery rings obtained from anesthetized dogs. The role of oxygen-derived free radicals was also investigated. Dogs were subjected to four 5-min episodes of left anterior descending coronary occlusion interspersed with 5 min of reperfusion followed by a final 60-min reperfusion period. The multiple occlusion-reperfusion protocol resulted in regional segment dysfunction (37 +/- 15% of preocclusion values at 60 min of reperfusion) and attenuated endothelium-dependent responses to acetylcholine, bradykinin, and the calcium ionophore, A23187. Responses to the endothelium-independent vasodilator, sodium nitroprusside, were unaffected. Infusion of superoxide dismutase (5,000 U/kg) and catalase (55,000 U/kg) markedly improved the recovery of myocardial function at 30 and 60 min of reperfusion and completely protected against vascular endothelial damage. These results suggest an important role for oxygen-derived free radicals in the myocardial and endothelial injury that occurs in this model of multiple stunned myocardium.

Role of mast cells in calcium ionophore (A23187)-induced peritoneal inflammation in mice

Inflammation ◽  
1994 ◽  
Vol 18 (2) ◽  
pp. 187-192 ◽  
Author(s):  
Tadimeti S. Rao ◽  
Alexander F. Shaffer ◽  
Jerry L. Currie ◽  
Peter C. Isakson
Keyword(s):  
Mast Cells ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Peritoneal Inflammation
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